應用田口實驗法設計強健性PID控制器於五自由度高速磁浮主軸

Abstract

磁浮軸承轉子系統具有非線性之動態特性，外力干擾問題嚴重，因此本論文採用具 強健性之田口實驗法來設計PID控制器，並結合分散控制之構想，設計出一組適用於此 轉子系統之分散式PID控制器，實驗結果發現此控制器對外力干擾之抑制效果均較分散 式PD控制器為佳。 田口實驗法主要有兩特色，首先，利用所有可能的組合找出影響響應品質之主要因 子及交互作用因子。其次，利用S╱N比以評估系統性能並可顯示系統於雜音因子作用對 統性能的影響。故田口實驗法為以控制因子可操作的範圍內將S╱N比最佳化，以減少雜 音因子對系統的影響。 最後將自行開發一組符合本系統之設計規格的電流驅動器，結合控制器、原型機和 相關周邊設備，進行空轉試驗，來瞭解此磁浮主軸之性能。並希望由實驗之結果，提供 更多有關磁浮軸承特性之資訊，以作為未來工業界將磁浮軸承應用於高速研磨與銑削的 基礎。

The dynamic characteristics of magnetic bearings are often suffered from many problems, such as nonlinearities, parameter variations and external disturbances. To solve these problems, we applied Taguchi method associated with the decentralized control to design a decentralized PID controller with robustness. The results show that the performance of the decentralized PID controller system is better than that of the decentralized PD control system in the ability of suppressing the external force except that chattering effect exists in the responses. In the study, the Taguchi method is employed to determine beast parameters in control rules for a decentralized PID control method. Two major characteristics of the Taguchi method are, firstly, the use of total possible combinations to estimate the main factor effect and some, not all, of the interaction. Secondly, signal-to-noise (S╱N) ratios are used to evaluate the system performance of a system in the presence of noise factor, so that the performance can be made insensitive to noise factor. For control systems with uncertainty, the Taguchi method is found to be effective to improve system performance. Finally, we developed a current driver circuit for a high speed spindle with five degrees of freedom supported by magnetic bearings. The prototype is tested under various operating conditions. We found that the control performance fulfills our design specifications, which directly verify our design methodology.